You might think that the difference between Nintendo's famous brothers is that one likes to wear red and the other wears green, or that one of them can sometimes jump a tad higher.

But there's another key difference.

Luigi, the creators of the next Luigi-starring game from Nintendo say, is more emotional. That is essentially what these developers said when I asked them to tell me how the brothers differed. We had this conversation as part of a transcontinental video conference call.

"Luigi, by nature, is sort of a little bit of a fearful and clumsy character, so that's something that provides a lot of opportunity for gameplay," Yoshihito Ikebata, the supervisor for Luigi's Mansion: Dark Moon, told me via a video uplink from Nintendo HQ in Kyoto.

"With Luigi you can also explore a wider range of emotions," added Brian Davis, a gameplay engineer at Next Level Games, the Vancouver, Canada-based studio that co-developed a pair of Mario-family soccer games for GameCube and Wii as well as the most recent Punch-Out. Davis and his colleague were chiming in from Nintendo of America's offices near San Francisco.

These were not the answers I was expecting. Sure, Mario's a mascot and therefore something of a generic everyman. I'd not thought of Luigi as more fleshed-out, as more emotional.

"He's kind of the underdog in the shadow of his brother," Davis' colleague Bryce Holliday, director at Next Level, said. "So he kind of has that fearful tension that always surrounds him. This game's about spooks and comedy. He just provides a wider range or reactions. Our animators have had a lot more fun kind of getting a wider range of emotions through to the player than Mario will. He just kind of does his pump-fist and jumps up. After 10 hours of pump-fist, it might be too much."

OK, that makes sense. Mario's a success and maybe a little bland. But Luigi? We can relate to Luigi better. (Plus: he's cooler.)

Luigi appears to spend a good chunk of the upcoming Luigi's Mansion Dark Moon oscillating between fear and glee. That's more than we'd get from Super Mario. Dark Moon will be out on 3DS on March 24. But I'll have much more from my unusual, globe-spanning interview with the game's developers in the coming days.